Control means



Nov. 17, 1936. o. F. cARLsoN CONTROL MEANS Filed May 9, 1934 4 Sheets-Sheet l fave/afar.- ascarfffiawfso/z Nov. 17, 1936. o. F. CARLSON CONTROL MEANS Filed May 9, 1934 4 Sheets-Sheet 2 f/z-mmior flsca-P F (0115012,

Nov. 17, 1936. o, CARLSQN 2,061,270

CONTROL MEANS Filed May 9, 1934 4 Sheets-Sheet 3 Nov. 17, 1936. o. F. CARLSON CONTROL MEANS Filed May 9, 1934 4 Sheets-Sheet 4 Patented Nov. '17, 1936' PATENT OFFICE CONTROL MEANS Oscar F. Carlson, Chicago, Ill., assignor to Oscar F. Carlson Company, Chicago, 111., a corporation of Illinois Application May 9, 1934, Serial No. 724,684

26 Claims. (Cl. 200-83) The present invention relates generally to control mechanisms and is particularly concerned with pressure limit control means arranged to operate circuit controlling means or other mechanisms when the pressure varies more than a given amount. The present invention is especially concerned with mechanisms wherein the pressure responsive portion thereof may be adjusted to accommodate the device for pressures l0 within various ranges and wherein, at the same time, the spread between the values at which the switch mechanism or other means operated in accordance with pressure is controlled may likewise be varied.

For example, in boiler installations and the like equipped with oil burners or other means having electrical control mechanism, it is desirable to control the heat output by shutting off the fire when the pressure in the boiler reaches 30 a given value and starting up the fire when the pressure falls to a predetermined minimum. In many cases, the aforesaid control is effected through switch mechanisms of various kinds and associated apparatus, adapted to be cut-in and cut-out according to variations of steam pressure within the boiler.

It is well known that, in such devices as those of the type referred to above wherein it is desired to maintain a substantially constant boiler pressure, the differential between the on and off positions should be smaller at lower heat demands than at higher heat demands in order to prevent excessive variations in the pressure, in the first instance, and to prevent too frequent operation of the switch mechanism and associated apparatus in the second instance.

With these factors in view, one of the principal objects of the present invention is to provide a simple, compact and sturdy pressure limit control device and to provide manually operated means for adjusting the differential for various operating conditions. More specifically, it is the purpose of the present invention to provide a pressure sensitive device embodying a spring biased sylphon bellows, so constructed and arranged that a comparatively light spring may be used for resisting the extension of the bellows due to the boiler pressure.

Another object of the present invention is the provision of a sylphon bellows construction embodying a spring movably carried by the bellows, in connection with motion multiplying means actuated by movement of the bellows due to pressure variations and reacting against the spring carried by the bellows. As a result of this construction, a relatively small displacement of the bellows occasions a comparatively large movement of the spring. Another object of the present invention is to so mount the spring and the bellows that the same form a compact and sturdy pressure sensitive unit.

Another object of the present invention is the provision of simplified mechanism for adjusting the device for higher or lower boiler pressures, and in this connection the preferred construction is such that the adjusting means reacts against a portion of the motion reversing mechanism referred to above for adjusting the spring means to accommodate the higher or lower absolute boiler pressures.

Still further, another object of the present invention is the provision of manually operated means for adjusting the differential between the on and off positions of the associated switch mechanism. In this connection, the present invention contemplates increasing the spread or differential at the higher boiler pressures by manual means which can be adjusted independently of the adjusting means for setting the device for higher or lower absolute boiler pressures. To this end, the present invention contemplates a member manually shiftable between the pressure responsive unit and the switch unit and so arranged with respect to the unit so that the point of application of the pressure unit is varied with respect to the portion of the switch unit operated thereby. More particularly, according to the principles of the present invention, the switch unit embodies a pivoted operating memher and the pressure unit includes a bodily movable member, and between these two members there is interposed a manually shiftable member which is moved by the bodily movable member of the pressure unit and reacts against the pivoted member of the switch unit for operating the switch. By manually adjusting the interposed member, the point of application of movement responsive to pressure variations can be disposed at a greater or lesser distance from the pivot axis of the pivoted member, thereby varying the amount of movement of the bodily movable member required to shift the switch mechanism from its off position to its on position and vice versa. An additional object of the present invention in this connection is the arrangement of the parts so that the switch mechanism is always thrown to one position when the boiler pressure falls to a predetermined minimum. Preferably, this so called constant position corresponds to the on position of the switch mechanism, so that the oil burner or other mechanism controlled by the instant device is always placed into operation whenever the pressure falls to a given value. Obviously, of course, these conditions could be reversed, or otherwise varied, as desired.

Still further, another object of the present invention is the provision of automatic means for adjusting the differential between the on and of! positions of the switch proportionally to the means adjusting the device for higher or lower boiler pressures.

These and other objects of the present invention will be apparent to those skilled in the art after a consideration of the following detailed description of the preferred structural embodiment which is illustrated in the accompanying drawings forming a part of this specification.

In the drawings:

Figure 1 is a general elevational view showing a device constructed according to the principles of the present invention;

Figure 2 is an enlarged section taken along the line 22 of Figure 1;

Figure 3 is a section taken along the line 3-3 of Figure 2 and showing the operating member of the switch mechanism;

I Figure 4 is a sectional view taken along the line 4-4 of Figure 2;

Figure 5 is a section taken along, the line 55 of Figure 4, looking downwardly on the manually shiftable member for varying the pressure differential between the on and off positions of the switch mechanism;

Figure 6 is a section taken along the line 65 of Figure 4, looking upwardly toward the manually shiftable member;

Figure 7 is a section taken along the line 1-1 of Figure 2, looking downwardly toward the movable end of the sylphon bellows;

Figure 8 is a side elevation of the parts shown in Figure 7, certain portions being broken away;

Figure 9 is a view similar to Figure 8 but taken at right angles thereto;

Figure 10 is an enlarged perspective of the bridge or abutment plate carried by the pressure responsive unit and along which the manually shiftable member for varying the pressure differential is slidable;

Figure 11 is an enlarged perspective view of one of the levers forming a part of the motion reversing means by which a relatively small movement of the bellows occasions a relatively large movement of the biasing spring means; and

Figures 12 and 13 are views, similar to Figures 2 and 4, showing a modifled form of the present invention in which the differential adjusting means is automatic. I

Referring now to the drawings, more particularly Figures 1 and 2, the reference numeral i indicates the casing enclosing the major portions of the pressure responsive device and serving as a base or support for a switch mechanism, indicated in its entirety by the reference numeral 2, mounted on the casing I. The casing l includes a lower hollow portion 4 and a closure casting 5, and the hollow casting section 4 includes'a closed end 5 terminating in or provided with afltting 8. On the interior of the hollow casing section 4 is a flanged portion Ill surrounding the opening leading to the fitting 8, and the flange i serves to support and receive a bellows II of the sylphon type, the lower end of the latter being sealed, as by soldering or the like, over the opening in the lower end of the casing.

The bellows I2 is extensible and contractible axially of its length, and the end of the bellows opposite the end sealed to the casing 4 is sealed to the flange I of a tubular member I! closing the upper end of the 'bellows l2- and forming, in connection therewith and the lower portion of the casing 4, a pressure chamber II. The tubular member I5 is provided with a cylindrical reentrant portion 20 having a closed lower end 2| adapted to seat on projections 22 carried by the casing adjacent the fitting 5 for limiting the contraction of the bellows l2, thereby establishing a minimum volume for the pressure chamber II. The flange I5 is sealed to the upper end of the bellows i2 in any manner desired, as by soldering or the like. I

The upper or outer end of the tubular member i6 is provided with a cylindrical section 25 which includes a flanged portion 25 having openings receiving projections 21 punched from the flange l5, by virtue of which the portion 25 is rigidly secured to the member I6 so as to form a part thereof. The upper section 25 is also cylindrical and of substantially the same diameter as the re-entrant portion 20 of the part l5. A spring 29 is disposed within the cylindrical portion 25 of the member l5 and bears at one end against the bottom 2| thereof. The upper end of the spring 29 receives a flanged collar 30, and the spring 29 is compressible within the cylindrical portion 20 to impart a bias to the movable end of the bellows i2 to resist expansion thereof under increase in pressure within the chamber ll.

Diametrically opposite portions of the section 25 are provided with slots 32, and the lower portions of the slots 32 are reduced to receive a pivot pin 35, the ends of which have grooves 38 adapted to receive the edges of the slots 32, thereby holding the pivot pin 35 in position just above the collar 30 on the outer or upper end of the spring 29, as best shown in Figures 2 and 4. Slidably and rotatably mounted on the central portion of the pivot pin 35 are twooppositely disposed levers 40 and 4|. Figure 11 illustrates the form of the levers and from that figure it will be observed that the lever 40 includes a long arm 45 and a short arm 44, together with an apertured flange or hub 45 by which the lever is mounted on the pivot pin 35. The other lever 4| is of the same construction. These levers 40 and U are so mounted on the pivot pin 35 that the long arm 43 of each of the levers extends outwardly of the upper tubular member section 25, through slots 41 and 45. The long arm of each of the levers terminates in a hook-like end 50 (see Figure 11), and these ends are adapted to bear against the flange 26 of the upper tubular section 25, this portion being carried by the flange I 5 of the tubular member I6 to which the upper end of the bellows I2 is sealed. The short arm 44 of each of the levers 40 and 4| is disposed, when the levers are oppositely arranged as indicated in Figure 4, within the tubular section 25 and is adapted to engage the spring collar 50, the inner ends of the short arms being also formed with hook-like ends. The pivot pin 35 is connected or anchored to the casing 4 by means which is capable of adjustment for varying the spring pressure to accommodate the device for various boiler pressures. Referring now to Figure 2, the reference numeral 50 indicates a shaft journaled in the casing I, the meeting edges of the casing sections 4 and 5 being provided with semi-circular recesses 5| and 62, respectively, accommodating the shaft, as best shown in Figures 8 and 9. The

adjusting shaft 60 carries a pair of axially spaced 15 circular cam members 64 and 05, best shown in Figures 2 and 4. The cam elements 94 and 05 are arranged on opposite sides of the levers 40 and 4| and bear against the pin 35 to maintain the same in a given position relative to the casing I.

FromFigure 4 it will be observed that the amount of compression of the spring 29 and the position of the flange I5 ot the bellows I2 will depend upon the angular position of the circular cam elements 64 and 85. In Figure 4, the cams are turned so as to impose the least amount of tension on the spring 29. Pressure within the chamber I I, communicated thereto by suitable conduits or the like connected with the fitting 9 at the lower end of the casing I, serves to expand the bellows I and to move the flange I upwardly. In so doing the levers 40 and 4| will be swung about the pivot pin 35, since the latter cannot move upwardly because of its contact with the adjusting cams 54. When the bellows I2 is expanded and the flange I5 moves upwardly, the longer arm of the lever 40 contacting with the flange causes the lever 40 to swing about its pivot '35 in a clockwise direction as viewed in Figure 4, and likewise the upward movement of the flange I5 causes the lever H to be swung about the pivot pin 35 in a counterclockwise direction. Thus the inner end of each of the levers serves to depress the spring collar 30 and to move the outer or upper end of the spring 20 toward the lower end thereof, but it will be observed that when the bellows I2 is expanded and the flange I5 moved outwardly, the lower end of the tubular portion I5 also moves outwardly,

carrying with it the lower or inner end-of the spring 29. By virtue of this construction, and by virtue of the motion multiplying levers, a relatively small amount of movement Otf the flange l5 occasions a displacement of one end of the spring 29 with respect to the other end which is materially greater than the movement of the flange. With the proportions illustrated in Figure 4, the ratio of movement of the flange I5 to the extent of compression of the spring 29 is in the order of 3 to 5.

It is to be noted that by virtue of the positioning of the spring 29 within the reentrant portion 20 of the tubular member, a pressure responsive unit is provided which, while securing the advantages outlined above, is quite compact. The slots 32, 41 and 4B are long enough to provide for the movement of the tubular section 25, not only under pressure changes within the chamber Ill but also the movement of the outer or upper end of the bellows I2 when the shaft 60 is turned to adjust the initial tension of the spring means 29. For turning the shaft 90, a knob I0 is provided and is preferably secured to the shaft by means of a screw II. A pointer I2 is provided for indicating the position of the earns 64 and 65, and therefore indicating the absolute pressure for which the pressure responsive device is adapted, and this pointeris carried by a plate 13 secured to the knob or to the shaft 90 in any manner desired. The pointer I2 moves over a dial formed on the casting 5, and stops I1 and I8 in the form of projections or the like are provided and are adapted to cooperate with the pointer 12 in limiting the rotation of the adjusting shaft 60. Obviously, of course, the dial 15 may be arranged for substantially 360 rotation of the knob I0 where such a range is desired.

As mentioned above, the reference numeral 2 indicates switch mechanism adapted to be operated by the pressure responsive mechanism enclosed within the casing I. The mechanism of a switch unit 2 forms per se no part of the present invention except in so far as certain novel relations with respect to the pressure unit are disclosed. The switch housing includes casing 90 enclosing the switch mechanism and forming a compartment 9| to accommodate the same. The housing 90 includes a flanged section 93 which is closed by a plate 94 having an upturned edge 95 which is pressed onto the flange 93 of the housing 90. An insulator plate 90 is interposed between the inner surface of the plate 94 and the housing 90, and both of the plates 94 and 90 are provided with a narrow slot 99 (see Figure 3) in the central portions thereof and adjacent an operating member I00v forming a part of the switch mechanism. The operating member I00 is pivotally supported, as at I 0|, upon suitable bracket means I02 or the equivalent, and a spring I03 is included in the switch mechanism for the purpose of biasing the operating lever I00 for movement toward a given position. The spring member I03 is extended, as at I04, adjacent the slot 98 and serves as a part of the switch operating member I00. The extended end I04 of the spring I03 extends in registry with the slot 98, as best shown in Figure 3.

In operating the switch 2 the member I00 is swung from one position to another about its pivot IOI, opening a circuit in one position and closing the circuit in another position. Binding posts I06 and I0'I form a part of the switch 2 and are separated by an insulator I 08 and supported on a base I09. The casing 90 includes a tab IIO having an aperture II I to receive and support the casing or conduit means adapted to be connected with the binding posts I06 and I0'I.- If desired, the connection between such conduit means (not shown) may be enclosed by a separate cover mounted on the housing 90. v

The means for operating the switch 2 from the pressure responsive unit includes a shiftable member interposed between the outer end of the tubular section 25 and the operating member I00 of the switch. Referring now more particularly to Figures 4, 5, and 6, it will be observed that the outer end of the tubular member 25 carries a bridge or abutment plate B disposed between the cams 64 and 05. As best shown in Figure 10, the bridge i 20 consists of a flanged member hav ing a flat portion 024% and attaching ears I22 and I123 terminating in hooked ends I 24 and I25 which, as best shown in Figure 4, are adapted to be hooked into the upper ends of the slots 4] and 48 to hold the bridge H20 in place. Slidable along the flat portion l2i of the bridge is a shiftable adjusting member H29, and this member is provided with an upwardly extending projection I which extends through the slot 98 and is in engagement with the operating member I00. The extended end I04 of the spring I03 provides a convenient surface against which the point I30 can hear. The base portion of the shiftable member I29 is slotted, as at I33 in Figure 6, and receives a link I34 which is connected at one end with the shiftable adjusting member I 29 by a cotter key I35 and at the other end the link I34 is connected by a cotter key I36 with a slidable plunger I38 shiftably mounted in one wall of the spacer casting 5 and provided with a head or thumb piece I40. At this point, the casting 5 is enlarged to provide for a transverse bore I42 in which is disposed a spring I and a ball I. The slidable plunger I30 is provided with a number of. notches I49 into which the ball I seats, thereby holding the plunger I00, and hence the shiftable member I29, in any one of a number of adjusted positions. The spring I is held in place by virtue of the casting seating against the upper edge of the casing 4. Preferably, the casting 5 is secured in place on the casing I by a plurality of screws I00, and the switch 2 is mounted on the casting 5 by screws ISI. The plunger I is prevented from rotating about its longitudinal axis by a pin I55 which is mounted in the upper end of the bore I42 and has a reduced portion I08 disposed in a slot I51 formed in the plunger I38 and held therein by the switch casing 90. As will be apparent, by grasping the head I00 the plunger may be pulled out or pushed in to a number of adjusted positions, and in so doing the member I29 will be shifted along the bridge I20 and along the operating lever I00 to ward and away from the axis IOI of the latter. Since the tubular member 25 moves bodily in accordance with pressure variations, the member I29 will have the same extent of movement whether it is disposed at one end or at the other end of the bridge I20. However, since the projection I30 moves toward or away from the axis IOI of the switch operating member I00, it will be observed that it will require a greater displacement of the tubular member 25 to operate the switch when the member I29 is moved away from the axis IOI than will be required when the member I29 is nearer the pivot IOI. In the construction illustrated in Figure 4, the shiftable member I29 is at the limit of its inner position, namely, a position nearest the pivot I'0I. It will also be observed that the plunger I39 is provided with five notches, in which case the member I29 may be shifted to five definite positions away from the pivot IOI. In its outermost position, the shiftable member I29 is approximately twice as far from the pivot axis IOI as in the position shown in Figure 4, and hence when the member I29 is shifted outwardly, a greater movement of the outer end of the bellows is required for operating the switch.

It will also be observed that the portion I00 of the switch operating member I00 along which the member I29 is adjustable is in parallelism with respect to the slot portion I2I of the bridge or abutment member I20. Since these surfaces along which the member I29 is adjustable are parallel, it will be apparent that the outer end of the tubular member 25. and hence the outer end of the bellows I2, will always return to approximately the same position when theswitch operating member I00 is-in one of its positions. With respect, however, to its other position, to throw the operating member from the one position to its other position will require twice as much movement of the outer end of the bellows I2 when the member I29 is in its outermost position than will be required when the member I29 is in the position shown in Figure 4.

This feature is of especial importance where the present construction is utilized for controlling the oil burners of boilers and the like. For example, in one installation the device was so con-. structed that with a boiler pressure of 4 oz. the spring 29 acted to contract the bellows I2 to such an extent that the operating member I00 of the switch was moved to a position to close' the oil burner circuit, and when the steam pressure reached a value of 16 oz. the bellows I2 had extended a sufficient amount, when the operating member I29 was in its innermost position, namely, that shown in Figure 4, to throw the switch operating member I00 to its 01! position; but if the operating member I29 was in its outer position, that is, when the plunger I00 was pulled out as far as possible, to throw the switch operating member I00 to its off position required a movement of the bellows corresponding to a pressure of 2 pounds However, by virtue of the parallel arrangement referred to above, in either case when the boiler pressure was reduced to 4 oz., the operating member I00 was thrown to circuit closing position in both cases. Thus, in one position of the plunger I30, there was a differential of 12 oz. while in the second or extreme outer position there was a differential of 36 oz. between the on and off positions of the switch, but in both cases the switch mechanism was thrown to its on position when the steam. pressure was reduced to 4 oz.

While reference was just made to the present invention as embodied in a device adapted for use with a low pressure boiler, it is to be understood that the principles of the present invention may be employed under other pressure conditions. The absolute pressure for which the device may be adjusted can be controlled by the position of the knob I0 while, as explained above, adjusts the cams 64 and 65 which shift the pivot pin 00, thereby adjusting the initial tension of the spring 29. Adjustment of the spring 29 in this manner does not, however, effect the differcntial adjustment mentioned above. One advantage of the above described differential adjustment is that the boiler pressure can be slightly increased by pulling out the plunger I38. For example, in the installation referred to above, the boiler pressure could be increased from 1 pound to 2 pounds by moving the shiftable member I29 from its innermost to its outermost position. Thus, where the switch mechanism would be thrown to its off position in the first instance when the boiler pressure reached 1 pound, in the second case the switch mechanism would not be thrown to its off position until the boiler pressure reached 2 pounds.

In many cases it may be desirable to dispense with the advantages of manually controlling the differential adjustment more or less independently of the adjustment of the knob I0, and for such cases the present invention contemplates the provision of means for interconnecting the absolute pressure adjusting mechanism with the differential adusting mechanism, somewhat along the lines of the device disclosed in my copending application, Serial No. 647,767, filed December 17, 1932, for a Pressure and differential control, in which the broad feature of automatically adjusting the differential with the main adjusting mechanism is disclosed and claimed. In Figures 12 and 13 I have shown control mechanism similar to that described above but embodying the automatic differential control in the form of interconnecting link means associated with the shiftable adjusting member I29 and the pair of spaced circular cam members 04 and 00 which are fixedly carried by the adjusting shaft 00, as described above.

The interconnecting means just referred to consists of a pair of links I10 and "I connected,

, respectively, at I12 and III with the cam members 00 and 95. The upper or outer ends of the links I70 and III are connected together by a spacer I11, and to this part the outerend of a generally horizontally disposed link I10 is cona-counterclockwise direction as viewed in Figure- I2, a thrust is exerted through the links Ill! and III on the link I18. This shifts the block I29 away from the pivot I M and, at the same time,

depresses the pin 35 and imparts additional compression to the spring 20. It is to be noted that the earns 64 and 68 in Figures 12 and 13 are disposed in the opposite position as compared with Figures 2 and 4. This, of course, does not affect the operation of the device, except to require that the knob 'lIi shall be turnedin a direction oppo-. site to the direction in which the knob shown in Figure 1 is turned. The reason the cams 64 and 85 are arranged to be moved as indicated in Figare 12 is that a movement in the indicated direction is desirable in order to shift the member I29 in the proper direction, namely, away from the pivot Ilil, when the device is arranged for higher boiler pressures by imparting additional compression to the spring 28.

It is to be noted in Figure 12 that the bridge member I20 has its upper surface, along which the abutment block or shiftable member I29 is movable, arranged in a substantially horizontal position and not exa'ctlyjn parallelism with respect to the end I M of the switch operating member I00. In Figure 12 these surfaces are arranged somwhat at an angle to one another, and likewise when the bellows I2 has been expanded by an increase in the boiler pressure and the switch lever IIIII thrown upwardly, the surfaces.

' are also arranged at an angle to one another.

By virtue of this construction, when the spring 28 is compressed by the rotation of the earns 64 and 65 in the direction of the arrow and the block I29 a considerable distance from the pivot II, the boiler tends to fall to a lower pressure before the burner is cut in, as compared with the pressure when the shiftable abutment member I29 is in a position closer to the pivot IOI. In other words, when the device is arranged for higher boiler pressures, the difierential between the on and off positions is spread in both directions from an intermediate point, rather than upweirdly from the same point, namely, four ounces in the mechanism previously described.

While I have shown and described above the preferred construction in which the principles of the present invention have been embodied, it will be apparent to those skilled in the art that my invention is not to be limited to the specific details shown and described above, but that, in fact, widely different means may be employed in the practice of the broader aspects of my invention.

What I claim, therefore, and desire to secure by Letters Patent is:

1. Control mechanism comprising pressure responsive means movable in response to variations in pressure, means operable throughout a given range for adjusting the responsiveness of said means, switch mechanism movable to on and 011 positions in response to movement of said pressure responsive means, operative connections between said pressure responsive means and said switch mechanism, and means controlled by said adjusting means throughout substantially the entire operating range thereof for adjusting said connections whereby to vary the operative relation between said pressure means and said switch mechanism an amount uniformly proportional to the adjustment of the responsiveness of said pressure responsive means.

2. Control mechanism comprising pressure responsive means movable in response to variations of pressure, means for adjusting the responsiveness of said means, a device including a pivoted part to be actuated by said movable means,

means spaced from the pivot axis of said part and subjecting the latter to the action of said pressure responsive means, and manually controlled means for shifting said last mentioned means relative to the pivot axis of said part for adjusting the extent of movement thereof rela-- tive to a given extent oi movement of said pressure responsive means.

3. Control mechanism comprising pressure responsive means movable in response to variations of pressure, means for adjusting the responsiveness of said means, a device to be actuated by said movable means and including a pivoted operating member, means actuated by said movable means and shiftable toward and away from the axis of said pivoted member for swinging the I latter in response to movement of said pressure responsive means, and means operative simultaneously with said first adjusting means for adjusting the position of said shiftable means.

4. Control mechanism comprising pressure responsive means including a member movable in response to variations of pressure and a casing enclosing said member, a device mounted on said casing and including a pivoted part adapted to be actuated by said movable means, an abutment plate carried by said member and movable therewith, and laterally shiftable means disposed between said abutment plate and said part and spaced from the pivot axis of the latter, said s'hiftable means being movable toward and away from said pivot axis to vary the point of reaction of said pressure responsive means on said device.

5. Control mechanism comprising pressure responsive means including a member movable in response to variations of pressure and an abutment plate carried thereby, a casing enclosing said pressure responsive means and said abutment plate, switch mechanism mounted on said casing and including a pivoted operating member disposed adjacent said abutment plate, a member disposed between said plate and said operating member and serving to transmit the motion of said pressure responsive member to said operating member, and means for shifting said last named member relative to the axis of said pivoted operating member and while in contact with both the latter and said abutment plate so as to vary the movement of said pressure responsive member corresponding to a given movement of said pivoted operating member.

6. Control mechanism comprising a casing, bellows means disposed within said casing and secured thereto at one end, a tubular member closing the other end of said bellows means and including a portion disposed within said bellows means, spring means disposed within said portion of the tubular member, means anchoring the outer end of said spring means to said casing, and a device bridging said anchorage means and connected with and actuated by the outer end of said tubular member.

7. Control mechanism comprising a casing, a sylphon bellows mounted within said casing and secured thereto at one end, a tubular member having an intermediate flanged portion secured to the other end of said sylphon bellows and including a portion disposed within the bellows and I a portion. extending outwardly thereof, spring bly associated with said spring means for taking the reaction thereof, and a device mounted on said casing and operatively connected with the outer end of said tubular member to be actuated thereby.

8. Control mechanism comprising a casing, a sylphon bellows sealed therein, a tubular member sealed to one end of the bellows and forming in connection with the bellows and said casing a pressure chamber, said tubular member including a portion disposed within the bellows and adapted toseat against a portion of the casing when said bellows is contracted, said tubular member also including a slotted portion extending outwardly from said bellows, spring means disposed within said flrst mentioned portion of the tubular member, a transverse member carried by said casing and disposed within said slotted portion of the tubular member to take the reactions of said spring means, and a device to be actuated carried by said casing and operatively connected with said last mentioned portion of the tubular member.

9. Control mechanism comprising a casing, a

sylphon bellows carried thereby, a tubular member carrbd by the bellows, spring means disposed for movement within said member and having one end bearing against the member, and motion reversing mechanism carried by the casing and including means movable with said member and reacting against the other end of the spring means carried by said member. 10. Control mechanism comprising a casing, a sylphon bellows carried thereby, a tubular member carried by the bellows, spring means disposed for movement within said member and having one end bearing against the member, lever means bearing at one end againstthe other end of said spring means and bearing at the other end against said member, pivot means supporting said lever means in the casing, whereby when the tubular member moves under the influence of pressure variations, both ends of said spring means are shifted towards or away from each other, and means carried by the casing-for ad- Justably shifting the position of said pivot means. 11. Control mechanism comprising a casing, a sylphon bellows sealed therein at one end, a tubular member sealed to the other end of said bellows and including a portion disposed within the bellows, spring means seated in said portion, a tubular member extending outwardly beyond said spring means and having diametrically opposite slots therein, a pin slidably mounted in said slots and against which the outer end of said spring means bears, and adjusting mechanism for tensioning said spring means comprising a shaft carried by said casing and disposed within said slots outwardly of said pin and including cam means carried by the shaft and bearing against said pin. I

12. Control mechanism comprising a hollow casing having an opening therein, a sylphon bellows sealed at one end to said casing over said opening, a flanged tubular member sealed to the other end of said bellows and including a reentrant cylindrical portion disposed on the interior of said sylphon bellows and serving in connection therewith and with said casing to define a pressure chamber, said tubular member being provided with an outwardly disposed portion extending beyond the flange thereof and provided with a plurality of slots therein, a pin slidably carried by the outer slotted portion of said tubular member, a pair of levers iournaled on said pin and each lever having one end extending outwardly of the tubular member and bearing against the flange portion thereof and an inner .end disposed within said tubular member, spring means biased between the inner end of said reentrant portion and. the inner ends of said levers, and means anchoring the pin to said casing to take the reaction of said spring means.

13. Control mechanism comprising a hollow casing having an opening therein, a sylphon bellows sealed at one end to said casing over said opening, a flanged tubular member sealed to the other end of said bellows and including a reentrant cylindrical portion disposed on the interior of said sylphon bellows and serving in connection therewith and with said casing to deflne a pressure chamber, said tubular member being provided with an outwardly disposed portion extending beyond the flange thereof and provided with. a plurality of slots therein, a pin slidably carried by the outer slotted portion of said tubular member, a pair of levers iournaled on said pin and each lever having one end extending outwardly of the tubular member and bearing against the flange portion thereof and an inner end disposed within said tubular member, spring means biased between the inner end of said reentrant portion and the inner ends of said levers, a transverse shaft journaled in said casing and disposed outwardly of said pin, and cam means carried by said shaft and bearing against said pin to adjustably tension said spring means within the tubular member, said cam means being disposed on opposite sides of said levers.

14. Control mechanism comprising a hollow casing having an opening therein, a sylphon bellows sealed at one end to said" casing over said opening, a flanged tubular member sealed to the other end of said bellows and including a reentrant cylindrical portion disposed on the interior of said sylphon bellows and serving in connection therewith and with said casing to deflne a pressure chamber, said tubular member being provided with an outwardly disposed portion extending beyond the flange thereof and provided with a plurality of slots therein, a pin slidably carried by the outer slotted portion of said tubular member, a pair of levers iournaled on said pin and each lever having one end extending outwardly of the tubular member and bearing against the flange portion thereof and an inner end disposed within said tubular member, spring means biased between the inner end of said reentrant portion and the inner ends of said levers, a transverse shaft disposed in parallelism with respect to said pin and Journaled in said casing, said shaft being disposed in the same slots as said pin and provided with circular cam members bearing against said pin, and means for rotating said shaft for adjusting the tension of said spring means.

15. Control mechanism comprising a hollow casing having an opening therein, a sylphon bellows sealed at one end to said casing over said opening, a flanged tubular member sealed to the other end of said bellows and including a reentrant cylindrical portion disposed on the interior of said sylphon bellows and serving in connection therewith and with said'casing to define a pressure chamber, said tubular member being provided with an outwardly disposed portion extending beyond the flange thereof and provided with a plurality of slots therein,'a pin slidably carried by the outer slotted portion of said tubular member, a pair oi! levers journaled on said pin and each lever having one end extending outwardly of the tubular member and bearing against the flange portion thereof and an inner end disposed withinsaid tubular member, spring means biased between the inner end of said reentrant portion and the inner ends of said levers, a transverse adjusting shaft journaled in said casing and disposed in the same slots as said pin and in parallelism with respect to the pin, a pair of circular cam members secured to said shaft and arranged to bear against said pin, said cam members being disposed on opposite sides 01' said levers and extending from the outer end of said tubular member, an abutment plate carried by the outer end of said tubular member and disposed between said cam members, said abutment plate having a flat portion disposed in a plane generally perpendicular to the direction oi. movement of said tubular member, a device mounted on said casing and adapted to be controlled by movements of said tubular member, and a member interposed between said plate member and said device and 1 adapted to be shifted across thefiat portion oi" said plate member for adjusting the relation between said-tubular member and said device to be actuated thereby.

16. Control mechanism comprising pressure responsive means including a casing and a member movable therein in response to variations of pressure, a device mounted on said casing and adapted to be controlled according to pressure and including a pivoted operating lever, an

. abutment plate carried by said movable member and including a flat portion disposed adjacent said operating lever, a member interposed between said abutment member and said lever and movable across the flat portion of the former toward and away from the pivot axis of the latter to adjust the operating relation between said abutment plate and said device and movable with respect thereto to vary the point of reaction of said pressure responsive means on said device, and means interconnecting said laterally shiftable means with said cam means whereby adjustment of the latter automatically positions said laterally shiftable means.

18. Control mechanism comprising pressure responsive means, a device to be actuated thereby, said device including a pivoted actuating member for operating the device and said pressure responsive means including a movable member andmeans shiftable along said movable member relative to the pivot axis of said actuating member for operating the latter from said movable member, said actuating member and said movable member being arranged in parallelism in one position 01' theactuating member, whereby movement of said shiftable means in this position will not ai'iectthe position 01' either the actuating member or the movable member relative to the other.

, 19. Control mechanism comprising pressure responsive means, a device to be actuated thereby and including an operating member pivoted for movement about an axis from one position to another, said pressure responsive means including a bodily movable member arranged to actuate said operating member, said bodily movable member includinga section disposed in parallelism with respect to said pivoted member in one position of a latter, and a connecting member shiftable across the face of said bodily movable member for transmitting movement therefrom to said pivoted operating member at different distances from the pivot axis of the latter, whereby said and comprising a shiftable abutment block and a pivoted member interposed between said means and said device, the abutment block being movable with said movable pressure responsive means and shiftable toward and away from the pivot axis of said member, and means carried by the casing and operatively connected with said abutment block to accommodate its movement with said movable pressure responsive means and arranged to shift said abutment block toward and away fromthe pivot axis of said pivoted member for adjusting the range or movement of one with respect to the corresponding range of movement of the other.

21. Control mechanism comprising pressure responsive means including a member movable in response to variations of pressure and an abutment plate carried thereby, a casing enclosing said pressure responsive means and said abut ment plate, switch mechanism mounted on said casing and including a pivoted operating member disposed adjacent said abutment plate, a member disposed between said plate and said operating member and serving to transmit the motion of said pressure responsive member to said operating member, and means carried by said casing for shifting said last named member to vary the throw of said pivoted operating member corresponding to a given movement of said" pressure responsive member, said means including a link pivotally connected with said shiftable member and arranged to accommodate the movement of the latter when the abutment plate is moved by said pressure responsive member.

22. Control mechanism comprising a casing, a sylphon bellows mounted within said casing and secured thereto at one end, a tubular member secured to the other end of the bellows and movable therewith, said tubular member including a portion disposed within the bellows and a portion extending outwardly thereof, spring means disposed within the inner portion of said tubular member, said outer portion of the tubular member being slotted, a transverse member carried bysaid casing and disposed within the slotted portion of said tubular member for taking the reaction of said spring means, and a device mounted on said casing and operatively connected with the outer end oi said tubular member to be actuated thereby.

23. Control mechanism comprising acasing, a sylphon bellows carried thereby, a tubular member carried by the bellows, spring means disposed for movement within said member and having one end bearing against the member, lever means bearing at one end against the other end oi said spring means and bearing at the other end against said tubular member, and'pivot means supporting said lever means in the casing, whereby when the tubular member moves under the influence of pressure variations both ends oi. said spring means are shifted towards or away from each other.

24. Control mechanism comprising a casing, a sylphon bellows sealed therein. a tubular member sealed to one end of the bellows and forming in connection with the bellows and said casing a pressure chamber, said tubular member including a portion disposed within the bellows and adapted to seat against a portion of the casing when said bellows is contracted, said tubular member also including a slotted portion extending' outwardly from said bellows, spring means disposed for movement within said member and having one end bearing against the member, a transverse member reacting against said casing and disposed within said slotted portion of the tiibiuarmembenandievermeanspivotedonsaid transverse member andbearing atoneend against theotherendoisaidspringmeansandbearing sttheotherendagainstsaidtubiuarmember. whereby when the tubular member moves under the influence oi pressure variations both ends of 'said spring means are shifted towards or away a from each other.

outer end of said spring means to said casing including a pair 0! oppositely directed levers pivotally connected with the casing and each having one end bearing against the outer end of said spring means, the other end of each lever bearing against said tubular member.

26. Control mechanism comprising a casing. bellows means disposed within said-casing and secured thereto at one end, a tubular member closing the other end of and secured to said bellows means, spring means disposed within and acting against said tubular member, "means extending to a point within the outer end of said tubular member for anchoring the outer end of said spring means to said casing, and a device bridging said anchoring means and connected with and actuated by the outer end of said tubular member.

OBCAR l". CARILSON. 

